Atypical ductal hyperplasia of the breast. Definition

Medical Definition: Atypical ductal hyperplasia of the breast

Benign (not cancerous), in which more than normal cells in the lining of the ducts of the breast and the cells look abnormal under a microscope. Having atypical ductal hyperplasia of the breast increases the risk of breast cancer. Also called ADH and atypical ductal hyperplasia.